This application claims the benefit of and priority from Japanese Application No. 2002-13109 filed Jan. 22, 2002, the content of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to a cap device detachably attachable to the member with a tank opening.
2. Description of the Related Art
Known fuel cap of the kind are disclosed in U.S. Pat. No. 6,202,879. Specifically, the fuel cap comprises a housing having a gasket disposed thereon, for providing closure to the opening of a filler neck; a cover disposed on the upper portion of the housing and having an operating handle; and an interlock mechanism disposed between the housing and the cover, for switching between a transmitting mode, in which rotational torque of the cover is transmitted to the housing, and a non-transmitting mode in which rotational torque is not transmitted.
The interlock mechanism comprises cantilevered engaging switches extended outwardly to either side of the operating handle. To install or remove the fuel cap, the operating handle is squeezed to cause the engaging switches to sandwich and hold a support shaft integral with the housing so that rotational force is transmitted to the housing, thereby allowing the cap to be installed or removed. With the fuel cap closed, the engaging switches do not sandwich the support shaft, so that the cover and handle turn freely with respect to the housing. Thus, if the cover and handle should be subjected to external force they will simply spin without rotating the housing, thereby preventing loss of seal by the gasket.
However, since the engaging switches are induced to sandwich and interlock with the support shaft by means of squeezing force applied to the handle when installing or removing the fuel cap, it is necessary to for the user to apply a high level of force in order to maintain the interlock, so poor ease of operation is a problem.
The present invention is intended to solve this problem of the prior art, and has as an object to provide a fuel cap that maintains a good seal even if subjected to external force, while at the same time providing superior ease of operation.
To solve the above problem, the present invention provides a cap device comprising a cap configured to open and close a tank opening. The cap comprises: a closer for closing the tank opening with air-tight sealing; a handle mechanism rotatably mounted on the closer, the handle mechanism having an operation portion that is operable to close and open the tank opening; and an interconnecting mechanism, provided between the handle mechanism and the closer, the interconnecting mechanism transmitting to the closer rotational torque in a closing direction and an opening direction when the rotational torque is applied to the handle mechanism to close and open the tank opening. The interconnecting mechanism comprises: a clutch switch having a closing position and an opening position, the clutch switch being configured to be switchable from the closing position to the opening position when a user operates the cap to open the tank opening; and an one-way clutch unit having a first transmission mode and a second transmission mode, the first transmission mode being a mode in which the one-way clutch unit transmits the torque applied to the handle mechanism in the closing direction to the closer within a predetermined range and rotates freely in the opening direction when the clutch switch is switched to the closing position, the second mode being a mode in which the one-way clutch unit transmits the torque applied to the handle mechanism in the opening direction to the closer when the clutch switch is switched to the opening position.
According to the cap device pertaining to the present invention, when the operating portion is squeezed and turned in the closing direction, as the one-way clutch unit of the clutch mechanism is normally in the interlocked state, the rotational torque of the operating portion is transmitted to the closure member via the one-way clutch unit so that the closure member moves to the closed position engaging the neck engaging portion in order to plug the tank neck. Conversely, when the operating portion is squeezed to unplug the tank neck, the clutch switch assumes the actuated state and the one-way clutch unit assumes the interlocked state in the installing direction, whereby rotational torque is transmitted to turn the closure member in the opening direction.
During the cap device removing operation, simply by squeezing the operating portion of the handle the clutch switch is placed in the actuated state to switch the clutch mechanism to the interlocked state by means of force supporting the operating portion, thus providing superior ease of operation.
With the closure member installed in the cap neck, in the event that the handle should be subjected to force in the opening direction the one-way clutch unit will simply turn freely since the clutch switch is not in the actuated state, and thus the housing body maintains closure of the filler neck so that the seal can be preserved.
In a preferred embodiment the clutch switch is constituted by a cantilever formed on the side wall of the operating portion and is designed to switch the one-way clutch unit to the interlocked state by flexing when the free end of the cantilever is pushed during the removal operation.
The clutch switch can be designed to have flexural rigidity when the operating portion is squeezed that is lower than flexural rigidity towards the direction of maintaining the one-way clutch unit in the interlocked state. Further, the one-way clutch unit may comprise clutch teeth arranged in a circle; and a clutch pawl for engaging and disengaging the clutch teeth. The clutch switch may be designed to restrict movement of the clutch pawl to effect shifting to the interlocked state.
With such a clutch switch arrangement, rather than using squeezing force applied by the user to the operating portion in order to maintain the clutch mechanism in the engaged state, i.e., for the clutch pawl to maintain pushing force against the clutch teeth, the high rigidity of the cross sectional secondary moment of the clutch switch is utilized, whereby the clutch mechanism will not switch to the disengaged state as long as the user does not relax the squeezing force applied to the operating portion so as to allow the clutch switch to return to its original position, thus providing superior ease of operation.
In a preferred embodiment the handle comprises a handle body furnished with a clutch switch; and a torque interlock member attached to the handle body and furnished with the one-way clutch unit.
Further, the handle may comprise a handle cover covering the handle body and constructed of pliable material that is deformable so as to transmit force inducing elastic deformation of the clutch switch. The handle cover covers the upper face of the handle body, protecting it from rainwater and the like.
In a preferred embodiment the cap device further comprises a torque mechanism that ceases to transmit torque when the handle is subjected to rotational torque in excess of a predetermined level in the opening direction. There are various possible arrangements for such a torque mechanism, for example, an arrangement comprising clutch teeth arranged in a circle, and a torque arm that rides up over the clutch teeth when subjected by the clutch teeth to rotational torque in excess of a predetermined level. With this arrangement, a tactile warning is provided when the clutch teeth of the torque mechanism rides up over the torque arm, allowing the user to ascertain that the closure member has been tightened to a predetermined level of torque, thus affording consistent seal force.